The chairman of NATO's Military Committee, General Petr Pavel, has denounced Donald Trump, the presumptive Republican nominee in the U.S. presidential election, for criticizing the alliance as obsolete.

"[Russian] President [Vladimir] Putin and some others may be pleased by this approach," Pavel said in an interview with Reuters on June 3. "To take such an approach would be a great mistake."

Trump has criticized the decades-old NATO alliance with mainly European nations as "obsolete" and too costly for the United States, saying other members are "not paying their fair share."

"Either they pay up, including for past deficiencies, or they have to get out," Trump said in April. "And if it breaks up NATO, it breaks up NATO."

"Statements like these are not necessarily damaging, but they are not useful," said Pavel, a Czech general.